Ship stabilizer using elongated weir means



Sept. 13, 1966 E. D. DREYFUS SHIP STABILIZER USING ELONGATED WEIR MEANS Filed Oct. 27, 1964 2 Sheets-Sheet l Irf LE-E K-I INVENTOR W F. M 0 3 d WM .M,

E. D. DREYFUS SHIP STABILIZER USING ELONGATED WEIR MEANS Sept. 13, 1966 2 Sheets-Sheet 2 Filed Oct. 27, 1964 Edward D. Oreyf'w a m m ATTORNEY$ United States Patent 3,272,170 SHIP STABILIZER USING ELONGATED WEIR MEANS Edward D. Dreyfus, Hyattsville, Md., assignor to John J.

McMullen Associates, Inc., New York, N.Y., a corporation of New York Filed 0st. 27, 1964, Ser. No. 406,748 9 Claims. (Cl. 114-125) This invention relates to a passive ship stabilizer and more particularly a ship stabilizer comprising elongated liquid storage means and an elongated longitudinally disposed weir means provided therein.

Passive stabilization systems for water going vessels have become quite well known in the art. These systems are characterized by comprising an elongated liquid storage means mounted athwartship in the vessel and containing a quantity of fluid or liquid which passes through proper damping means in response to the roll of the vessel, whereby the transferring liquid may pass from one end of said liquid container to the other and imparts a stabilization moment to the vessel. It is a purpose of the present invention to provide an improved system over the above-mentioned passive stabilization systems for water going vessels.

It is an object of the present invention to provide a passive ship stabilization system comprising an elongated liquid storage means and a longitudinally elongated weir or dam means mounted in the center of said liquid storage means so that the amount of fluid needed in said stabilization system is substantially reduced and the stabilizing moment developed per pound of liquid in the system (efliciency) is increased.

It is another object of the present invention to incorporate an elongated weir means in a passive stabilization system which cooperates with nozzle means in the respective wing tanks thereof so that the efliciency of the system is greatly increased.

Other and further objects of the present invention will become apparent upon the following detailed description when taken in view of the appended drawings in which:

FIG. 1 is a schematic representation of a ships hull showing one example of the location of the passive stabilization system of the present invention;

FIG. 2 is a horizontal sectional view of the present invention taken along the line 2-2 of FIG. 1, with the liquid omitted;

FIG. 3 is a vertical longitudinal sectional view taken along line 3-3 of FIG. 2; and

FIG. 4 is a vertical transverse sectional View taken along line 4-4 of FIG. 3.

Referring now to FIG. 1, there is illustrated a ships hull having the ship stabilization system 12 mounted between two decks thereof, said stabilization system having a longitudinal axis which extends substantially across the entire dimension of ship 10. A body of liquid is disposed within the stabilization system 12 and a portion of said body of liquid transfers from one side of the stabilization system 12 to the other in response to the roll of the vessel 10 so that a stabilization moment is applied to vessel 10 in a manner more fully described below.

Referring now to FIGS. 2-4, it can be seen that the stabilization system comprises an elongated tank 14 having side plates 16 and end plates 18. As best seen in FIG. 2, the longitudinal dimension is substantially greater than the transverse dimension of tank 14. The side plates 16 and end plates 18 are preferably welded or otherwise mounted between two decks of the ship so that the upper deck 21 acts as a top and the lower deck 22 acts as the bottom for tank 14.

An elongated weir or dam 20 is disposed substantially symmetrical within tank 14. Said dam 20 comprises a 3,272,178 Patented Sept. 13', 1966 pair of plates 26 mounted transversely across tank 14, having one end integral with the bottom 22 of tank 14 and the other end terminating spaced from the top of tank 14. Plates 26 are mounted at an angle with respect to the vertical and both said plates 26 are inclined toward the center of tank 14 for a purpose to be described below. A horizontally mounted plate 28 extends from one side plate 16 to the other and between the top ends of inclined plates 26. In the preferred embodiment, weir 20 extends along approximately one-half the longitudinal dimension of tank 14. Plate 28 can have a roughened surface so that kinetic energy of fluid flowing thereover is dissipated in a manner described more fully below.

A plurality of tubes 30 cooperate with partitions 32 to define plurality of vertically arranged nozzles 34. Nozzles 34 cooperate with end plates 18 to form a pair of wing tanks located at the extremities of tank 14. The function of nozzles 34 is to dissipate kinetic energy of liquid moving therethrough and also to dampen the movement of fluid within tank 14 to some extent.

Pipe 36 is connected with and communicates through plates 26, said pipe 36 having a conventional manual valve 38 which selectively controls the movement of fluid through pipe 36. The only purpose of pipe 36 and valve 38 is to enable communication between one side of tank 14 and the other for the purpose of draining through conventional drains (not shown). During normal stabilizing operation, valve 38 is normally closed and no movement of fluid takes place through pipe 36.

A body of water is disposed throughout tank 14 and has the same liquid level throughout when the body of liquid is in a static state. The system should be designed such that the static liquid level throughout tank 14 is approximately twice the distance between plate 28 and the floor of tank 14.

The operation of the system will now be described in detail. When the ship is riding in a calm sea and is not experiencing roll, the distribution of liquid within the respective wing tanks will be substantially the same so that no upstanding forces are applied to the ship. However, when the vessel is in a rolling condition such as encountered in unsheltered waters, the ship will roll at a natural frequency determined by the mass distribution of the ship. By adjusting the static liquid level of the body of fluid within tank 14, the natural frequency of the stabilization system 12 can be tuned to the natural frequency of roll of the ship. Since the stabilization system 14 is entirely passive, the frequency of the stabilization system will be out of phase with the natural frequency of roll of the vessel so that stabilization forces and moments are imparted to the vessel much in the same manner as described in United States Patent No. 3,054,373.

The elongated weir defined by plates 26 and 28 functions to decrease the amount of liquid necessary for imparting optimum stabilization moments to the vessel. It is believed that the most inefficient portion of liquid within the passive stabilization system is that found in the center bottom of the elongated tank such as tank 14. The elongated weir 20 of the present invention functions to remove this inefficient mass of liquid and the effects thereof and yet enables suflicient liquid transfer thereover so that optimum stabilization moments can be imparted to the vessel.

Therefore, as the ship rolls in its natural frequency, there will be liquid transfer from the higher of the two Wing tanks, through the associated nozzles 34, over the elongated weir 20, through the nozzles 34 associated with the lowermost wing tank, and into the lowermost Wing tank. Substantial amounts of kinetic energy are dissipated due to the fluid transfer and pressure drop at the nozzles 34 associated with the wing tanks, and furthermore, due to the roughened surface of plate 28. Plates 26 are inclined at an angle toward the center of tank 14 to enable a greater amount of liquid transfer to take place. Although it is not anticipated that an increment of water will move from one wing tank to the other during a complete cycle of roll, it is recognized that when viewing the body of liquid in tank 14 as a whole, the flow would be from one wing tank through the nozzle system, over the elongated weir 20, and into the opposite wing tank.

It is to be understood that any suitable type liquid can be used in the system without departing from the spirit of the present invention. Liquids such as fuel oil, bunker oil, sea water, and the like can be used. It can be seen from the above description that proper stabilization can be imparted to the ship with increased efficiency. This is afforded by the present design of the stabilization system and the elongated weir means 20 which eliminates great ineflicient volumes of water.

It is to be further understood that other and various modifications can be made to the persent disclosure without departing from the spirit of the present invention.

What is claimed is:

1. A stabilization system for ships and the like comprising an elongated enclosed tank mounted in the ship with its longitudinal axis extending transverse to the longitudinal axis of the ship, said tank having a pair of wing portions at opposite ends thereof, and an interconnecting portion extending from one wing portion to the other, an elongated weir mounted on the bottom of said interconnecting portion and having a top spaced below the top of said tank, said weir top being mounted generally in a horizontal position and extending throughout a major part of the length of said interconnecting portion, said weir also extending from one side of said tank to the other and having a downwardly sloping end plate extending from each end of said weir top to the tank bottom, a body of liquid partially filling said tank to a predetermined static level, the top of said tank at said inter-. connecting portion being above said static liquid level to define an air space above said liquid body and below said tank top.

2. A stabilization system as set forth in claim 1, wherein each end plate of said weir slopes outwardly as well as downwardly to the bottom of said tank.

3. A stabilization system as set forth in claim 1 further comprising liquid transfer restricting means mounted in each wing portion of said tank.

4. A stabilization system as set forth in claim 3 wherein said restricting means comprises elongated members positioned closer to the adjacent weir end than to the respective tank end,

5. A stabilization system as set forth in claim 4 wherein said members extend vertically and are spaced from each other laterally across said tank.

6. A stabilization system as set forth in claim 5 wherein said members extend from the bottom to the top of said tank.

7. A stabilization system as set forth in claim 1 wherein the weir extends longitudinally substantially throughout the length of said interconnecting portion.

8. A stabilization system as set forth in claim 1 wherein the upper surface of the weir top is roughened, and said system further comprising a pipe communicating with said wing portions through said end plates, and :a valve located in said pipe to selectively enable liquid flow from one wing portion to the other through said pipe.

9. A stabilization system for a ship and the like comprising an elongated tank mounted across said ship, said tank having a pair of wing portions at opposite ends thereof and an interconnecting portion extending from one wing portion to the other, a flat horizontally disposed plate extending from one side of said tank to the other and having longitudinal ends symmetrically positioned in said tank, said plate extending substantially throughout the length of said interconnecting portion, said plate being spaced vertically between the top and bottom of said tank, a body of liquid within said tank having a static liquid level between said tank top and the upper surface of said plate such that an air space is defined between said tank top and said static liquid surface, said static liquid surface being continuous in said wing and interconnecting portions, an end plate mounted at each end of said flat plate and extending downwardly therefrom to direct a portion of said liquid body over the top of said flat plate when transferring in response to the roll of the ship, said system further comprising means for enabling liquid to transfer from one wing portion toward the other beneath said plate.

References Cited by the Examiner UNITED STATES PATENTS 3,083,674 4/1963 Ripley 1l4l25 3,165,085 1/1965 Ripley 114-125 FOREIGN PATENTS 1,153,283 9/1963 Germany.

MILTON BUCHLER, Primary Examiner.

T. M. BLIX, Assistant Examiner. 

1. A STABILIZATION SYSTEM FOR SHIPS AND THE LIKE COMPRISING AN ELONGATED ENCLOSED TANK MOUNTED IN THE SHIP WITH ITS LONGITUDINAL AXIS EXTENDING TRANSVERSE TO THE LONGITUDINAL AXIS OF THE SHIP, SAID TANK HAVING A PAIR OF WING PORTIONS AT OPPOSITE ENDS THEREOF, AND AN INTERCONNECTING PORTION EXTENDING FROM ONE WING PORTION TO THE OTHER, AN ELONGATED WEIR MOUNTED ON THE BOTTOM OF SAID INTERCONNECTING PORTION AND HAVING A TOP SPACED BELOW THE TOP OF SAID TANK, SAID WEIR TOP BEING MOUNTED GENERALLY IN A HORIZONTAL POSITION AND EXTENDING THROUGHOUT A MAJOR PART OF THE LENGTH OF SAID INTERCONNECTING PORTION, SAID WEIR ALSO EXTENDING FROM ONE SIDE OF SAID TANK TO THE OTHER AND HAVING A DOWNWARDLY SLOPING END PLATE EXTENDING FROM EACH OF SAID WEIR TOP TO THE TANK BOTTOM, A BODY OF LIQUID PARTIALLY FILLING SAID TANK TO A PREDETERMINED STATIC LEVEL, THE TOP OF SAID TANK AT SAID INTERCONNECTING PORTION BEING ABOVE SAID STATIC LIQUID LEVEL TO DEFINE AN AIR SPACE ABOVE SAID LIQUID BODY AND BELOW SAID TANK TOP. 